Dawn of a new era of antibody-drug conjugates and bispecific T-cell engagers for treatment of multiple myeloma: a systematic review of literature

Multiple myeloma (MM) remains an incurable disease with the majority of patients experiencing disease relapse despite response to initial therapy. Antibody-drug conjugates (ADCs) and bispecific T-cell engagers are innovative immunotherapeutic approaches currently in development for the treatment of MM. This systematic review summarizes the efficacy and safety of ADCs and bispecific T-cell engagers in relapsed refractory (RR) MM patients from 2010 to date. Comprehensive literature search was conducted on PubMed, EMBASE, Wiley Cochrane Library, Web of Science, and Clinicaltrials.gov. A total of 13 studies (n = 529) met inclusion eligibility. All studies were prospective in nature investigating ADCs or bispecific T-cell engagers in RR MM; 10 trials were phase 1 and 3 were phase 2. The median age of patients ranged from 24 to 82 years. Among trials with ADC regimens, the overall response (OR) ranged from 34 to 60% and complete response (CR) ranged from 3 to 6%. The most common non-hematologic adverse event (AE) of ADCs was keratopathy, while anemia and thrombocytopenia were the most common hematological AEs. With bispecific T-cell engagers, ORR ranged from 31 to 83%, CR ranged from 7 to 22%, and partial response (PR) ranged from 5 to 16%. The most common non-hematologic AE of bispecific T-cell engagers was cytokine release syndrome (CRS) while the most common hematological AE was neutropenia. Initial data appears to show good clinical activity and tolerable safety profiles, making ADCs and bispecific T-cell engagers promising agents for RRMM. Future studies with newer combinations and a longer follow-up are needed to determine the precise role of these novel therapies in the evolving paradigm of MM treatment.